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| United States Patent |
5,312,792
|
|
Roberie
|
May 17, 1994
|
Catalytic compositions
Abstract
Crystalline aluminosilicate zeolite Y which contains phosphorus and its use
in the preparation of hydrocarbon conversion catalysts.
| Inventors:
|
Roberie; Terry G. (Ellicot City, MD)
|
| Assignee:
|
W. R. Grace & Co.-Conn. (New York, NY)
|
| Appl. No.:
|
916460 |
| Filed:
|
July 20, 1992 |
| Current U.S. Class: |
502/60; 502/79 |
| Intern'l Class: |
B01J 029/08 |
| Field of Search: |
502/60,79
208/114
|
References Cited
U.S. Patent Documents
| 3354096 | Nov., 1967 | Young | 252/435.
|
| 4115424 | Sep., 1978 | Unland et al. | 252/432.
|
| 4259212 | Mar., 1981 | Gladrow et al. | 252/455.
|
| 4340465 | Jul., 1982 | Miller et al. | 208/120.
|
| 4357265 | Nov., 1982 | Chiang | 252/455.
|
| 4431517 | Feb., 1984 | Nevitt et al. | 208/111.
|
| 4454241 | Jun., 1984 | Pine et al. | 502/68.
|
| 4465780 | Aug., 1984 | Pine | 502/68.
|
| 4483764 | Nov., 1984 | Hensley, Jr. et al. | 208/111.
|
| 4498975 | Feb., 1985 | Pine et al. | 208/114.
|
| 4504382 | Mar., 1985 | Pine | 208/114.
|
| 4567152 | Jan., 1986 | Pine | 502/64.
|
| 4584091 | Apr., 1986 | Pine | 208/114.
|
| 4765884 | Aug., 1988 | Walker et al. | 208/89.
|
| 4839319 | Jun., 1989 | Schuette et al. | 502/79.
|
| 4970183 | Nov., 1990 | Nakamoto et al. | 502/68.
|
| 5110776 | May., 1992 | Chitnis et al. | 208/114.
|
| Foreign Patent Documents |
| 0095364 | Oct., 1986 | EP.
| |
| 0252761 | Jan., 1988 | EP.
| |
| 0479485 | Apr., 1976 | SU.
| |
Primary Examiner: Dees; Carl F.
Attorney, Agent or Firm: Savage; Arthur P.
Parent Case Text
This is a continuation of application Ser. No. 593,834, filed Oct. 5, 1990
(now abandoned).
Claims
I claim:
1. A method for preparing phosphorus-containing ultrastable Y-zeolite which
comprises:
(a) ion-exchanging and washing sodium Y zeolite having a unit cell
dimension of about 24.53 to 24.72 .ANG. with an ammonium salt solution and
water to obtain a Y-zeolite which contains 1 to 5 weight percent Na.sub.2
O;
(b) combining the washed Y-zeolite of step (a) with an aqueous solution of
a phosphorus compound selected from the group consisting of H.sub.3
PO.sub.4, NH.sub.4 H.sub.2 PO.sub.4, (NH.sub.4).sub.2 HPO.sub.4, and Na
H.sub.2 PO.sub.4 to obtain a Y-zeolite that contains about 0.1 to 5 weight
percent P.sub.2 O.sub.5 ;
(c) heating the phosphorus-containing Y-zeolite of step (b) in the presence
of steam to obtain a phosphorus-containing ultrastable Y-zeolite having au
nit cell dimension of about 24.45 to 24.60 .ANG.; and
(d) washing the phosphorus-containing ultrastable Y-zeolite of step (c) to
remove sodium ions.
2. The method of claim 1 wherein the Y-zeolite of step (b) is heated at a
temperature of 500.degree. to 750.degree. C. in the presence of 10 to 100
percent steam.
3. The method of claim 1 wherein the phosphorus-containing ultrastable
Y-zeolite of step (d) contains 0.7 to 2.0 weight percent P.sub.2 O.sub.5.
4. The method of claim 1 wherein the product of step (b) is spray dried.
5. The method of claim 1 wherein the phosphorus compound is H.sub.3
PO.sub.4.
6. The method of claim 1 wherein the phosphorus-containing ultrastable
Y-zeolite obtained in step (c) has a unit cell dimension of 24.52 to 24.58
.ANG..
7. The method of claim 1 wherein the phosphorus-containing ultrastable
Y-zeolite obtained in step (c) is combined with inorganic oxide matrix
components selected from the group consisting of clay, silica, alumina,
silica/alumina sol and mixtures thereof, spray dried and washed to obtain
a fluid catalytic cracking catalyst.
8. The phosphorus-containing ultrastable Y-zeolite prepared by the method
of claim 1.
Description
The present invention relates to catalytically active zeolites, and more
specifically to phosphorus/zeolite Y compositions which are active for the
conversion of hydrocarbons.
Crystalline aluminosilicate zeolites, particularly synthetic faujasite,
i.e. zeolite Y, have been widely used in the preparation of hydrocarbon
conversion catalysts, such as catalytic cracking and hydrocracking
catalysts.
Thermally and chemically modified Y-zeolites, such as ultrastable Y zeolite
(USY) and calcined rare-earth exchanged Y zeolite (CREY) are included in
many commercial hydrocarbon conversion catalysts that are used to convert
heavy hydrocarbon feedstocks into more valuable products such as gasoline
and diesel fuel.
More recently, Y-zeolite catalysts which include phosphorus or phosphorus
compounds have been described in the patent literature.
EP 095 364 B1 discloses catalytic cracking catalysts that contain clay
based and synthetic Y-zeolites which are modified by the addition of
phosphorus to enhance catalytic activity for the conversion of hydrocarbon
feedstocks.
EP 0 252 761 A2 discloses cracking catalysts that contain a pretreated
phosphorus/ultrastably Y zeolite.
It is an object of the present invention to provide novel phosphorus
containing Y-zeolite compositions.
It is another object to provide phosphorus containing Y-zeolites that may
be readily converted into highly active phosphorus/ultrastable-Y
hydrocarbon conversion catalysts.
It is a further object to provide an economic method by which phosphorus
modified ultrastable-Y zeolite containing catalysts may be manufactured
and used on a commercial scale.
These and still further objects will become readily apparent to one
skilled-in-the-art from the following detailed description and specific
examples.
Broadly, my invention contemplates the preparation of phosphorus modified
Y-zeolites wherein a partially hydrogen, ammonium exchanged sodium Y
zeolite (Na, H, NH.sub.4 Y) is combined with a phosphorus compound such as
phosphoric acid NH.sub.4 H.sub.2 PO.sub.4, (NH.sub.4).sub.2 H PO.sub.4 and
NaH.sub.2 PO.sub.4 to obtain a novel phosphorus containing zeolite-Y
composition that may be readily converted to phosphorus/ultrastable-Y
zeolite (P/USY).
More specifically, I have found that highly active phosphorus/ultrastably-Y
zeolites may be prepared by the following process:
1) A sodium Y-zeolite (NaY) having a unit cell dimension of about 24.63 to
24.72 .ANG. is ion-exchanged and washed with an ammonium salt solution and
water to obtain a partially exchanged Na, H, NH.sub.4 Y that contains 1.0
to 5.0, and preferably 2.5 to 4.5, weight percent Na.sub.2 O.
2) The Na, H, NH.sub.4 Y is then combined with an aqueous phosphorus
solution such as phosphate acid at a pH of about 4 to 7, and dried at a
temperature of 20.degree. to 350.degree. C., preferably spray dried, to
obtain a novel phosphorus containing Na, H, NH.sub.4 Y zeolite (P/Na, H,
NH.sub.4 Y) that contains about 0.1 to 4 and more preferably 0.7 to 2
weight percent phosphorus expressed as P.sub.2 O.sub.5.
3) The P/Na, H, NH.sub.4 Y is then heated in the presence of steam (10 to
100%) at a temperature of 500 to 700.degree. C. for 0.5 to 2 hours to
obtain a P/USY zeolite having a unit cell of about 24.45 to 24.60 .ANG.
and preferably 24.52 to 24.58 .ANG..
The P/USY zeolite obtained by the above process is particularly active for
the catalytic cracking of hydrocarbons when combined with an inorganic
oxide matrix such as silica, alumina, silica-alumina sols and gel and clay
in accordance with the teaching of U.S. Pat. Nos. 3,650,988, 3,867,308,
3,957,689, CA 967,136 and U.S. Pat. No. 4,458,023. It is also contemplated
that the P/USY may be exchanged with metal cations such as rare-earths
(Ce, La, etc.), as well as Group II, VI and VIII metals such as Ni, Cr and
Mg.
In a particularly preferred embodiment the P/USY, obtained in 3) above is
combined with inorganic oxide matrix components such as clay and
silica/alumina-sol in an aqueous slurry, which is then spray dried, and
washed to remove Na.sub.2 O.
It is contemplated that the steam calcination step may take place during
the manufacturing process or during use of the catalyst in a catalytic
conversion process, such as fluid catalytic cracking (FCC).
The catalyst compositions contemplated herein will contain 10 to 80 weight
percent P/USY, 3 to 30 weight percent alumina, silica or silica sol/gel
binder and the balance clay (preferably kaolin). In addition the catalysts
may contain particulate alumina, acid/thermal modified clay, additional
zeolites/molecular sieves such as ZSM-5, zeolite Beta, USY, CREY, ALPO and
SAPO, as well as combustion/oxidation additives such as Pt and/or Pd, and
SOx conversion control sorbents such as RE/AL.sub.2 O.sub.3, particularly
La/Al.sub.2 O.sub.3 compositions.
The P/USY catalytic cracking compositions, when used under FCC
reaction/regeneration conditions of 455.degree. to 565.degree.
C./575.degree. to 820.degree. C. to crack hydrocarbon feedstocks such as
gas oil, residual oil and mixtures thereof, are particularly selective for
the production of gasoline fractions. In addition, the compositions of the
present invention find use as catalysts for hydrocracking, isomerization,
and hydroprocessing.
Having described the basic aspects of the invention, the following examples
are given to illustrate particular embodiments.
EXAMPLE I
Preparation of Na, H, NH.sub.4 Y
20,000 g of NaY having a unit cell dimension of 24.65 .ANG. was ion
exchanged with a 10% solution of ammonium sulfate at 80.degree. C. for
one-half hour and washed free of sulfate. The procedure was repeated,
after which the sieve was dried twelve hours at 110.degree. C.
The resulting product had the following characteristics:
Chemical Analysis (Wt. %)
______________________________________
SiO.sub.2 71.37
Al.sub.2 O.sub.3
24.42
Na.sub.2 O 4.05
TV 26.71
______________________________________
Physical Properties
Unit Cell 24.70 .ANG.
EXAMPLE II
Preparation of P/Na, H, NH.sub.4 Y
4757 g of the Na, H, NH.sub.4 Y obtained in Example I was added to 31285 g
of water. To this was added 690 g of 20% H.sub.3 PO.sub.4. The resulting
mixture having a pH of 4.7 was thoroughly agitated and spray dried using a
gas inlet temperature of 316.degree. C. and a gas outlet temperature of
149.degree. C.
The resulting product had the following characteristics.
Chemical Analysis (Wt. %)
______________________________________
SiO.sub.2 71.41
Al.sub.2 O.sub.3
25.13
P.sub.2 O.sub.5
0.80
Na.sub.2 O 3.88
TV 25.26
______________________________________
Physical Properties
Unit Cell 24.70 .ANG.
EXAMPLE III
Preparation of P/USY
5000 g of P/Na, H, NH.sub.4 Y of Example II was heated at 650.degree. C. in
the presence of 100% steam for 1 hour.
The resulting product had the following characteristics.
Chemical Analysis (Wt. %)
______________________________________
SiO.sub.2 71.41
Al.sub.2 O.sub.3
25.13
P.sub.2 O.sub.5
0.80
Na.sub.2 O 3.88
______________________________________
Physical Properties
Unit Cell 24.54 .ANG.
EXAMPLE IV
Properties of FCC Catalyst from P/USY
3035 g of the P/USY obtained in Example III was combined with 944 g of
alumina powder, 6000 g of silica-alumina sol, and 1347 g clay. The mixture
was spray dried and the resulting catalyst washed to reduce the soda
level. The catalyst was dried 150.degree. to 175.degree. C. for twelve
hours before being steamed at 1500.degree. F. (815.degree. C.) for four
hours and 1 atmosphere of steam partial pressure.
The resulting catalyst had the following properties.
Physical Properties
______________________________________
Steamed as above 174 m.sup.2 g
Fresh surface area (3 hrs. @ 1000.degree. F.)
285 m.sup.2 g
______________________________________
EXAMPLE V
Evaluation of FCC Catalysts
Samples of catalysts prepared in Example IV were evaluated by using the
procedure set forth by F. G. Ciapetta and D. S. Henderson, entitled
"Microactivity Test for Cracking Catalysts", Oil and Gas Journal, Vol. 65,
pages 89-93, Oct. 16, 1967 under the following conditions.
(a) Evaluation at constant Catalyst to Oil Ratio:
______________________________________
Temperature 980.degree. F.
Catalyst/Oil Ratio
4
Feedstock Sour Import Heavy Gas Oil
Space Velocity (WHSV.sup.-1)
30
______________________________________
The results are summarized in Table I below.
TABLE I
TABLE I
______________________________________
Catalyst Example IV Control*
______________________________________
Conversion (wt. % of feed)
71 62
Gasoline C.sub.5 + wt. %
47.7 42.0
LPG C.sub.1 - C.sub.4 wt. %
20.3 17.4
Coke wt. % 2.9 2.3
H.sub.2 wt. % 0.11 0.08
______________________________________
*Catalysts of Example V contain USY in lieu of P/USY.
(b) Evaluation at constant Conversion
The evaluation procedure of (a) was repeated at a constant conversion.
The results are summarized in Table II below.
TABLE II
The above Examples clearly indicate that valuable FCC catalysts may be
obtained using the teachings of my invention.
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